# File lib/phusion_passenger/utils.rb, line 1004
        def self.list_trappable
                ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : "ruby"
                case ruby_engine
                when "ruby"
                        result = Signal.list
                        result.delete("ALRM")
                        result.delete("VTALRM")
                when "jruby"
                        result = Signal.list
                        result.delete("QUIT")
                        result.delete("ILL")
                        result.delete("FPE")
                        result.delete("KILL")
                        result.delete("SEGV")
                        result.delete("USR1")
                else
                        result = Signal.list
                end
                
                # Don't touch SIGCHLD no matter what! On OS X waitpid() will
                # malfunction if SIGCHLD doesn't have a correct handler.
                result.delete("CLD")
                result.delete("CHLD")
                
                # Other stuff that we don't want to trap no matter which
                # Ruby engine.
                result.delete("STOP")
                
                return result
        end